Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 112-116). Also available via the Internet.

This thesis presents an application of a geographical information system (GIS) in propagation prediction. The motivating force behind this work is the need for accurate and efficient site-specific propagation prediction tools for personal communication system (PCS) design. Site-specific information including terrain and building attributes is vast and complex, and needs specialized handling. A geographical information system provides these capabilities, and relieves the propagation analysis tools of the burden of data management. This work focused on harnessing the relevant abilities of a GIS for aiding the current propagation prediction software. GRASS (Geographical Resources Analysis Support System) GIS has been used for data handling, transformation, and analysis. Schemes and techniques were developed for operations on site-specific data as used in propagation prediction. Attention was paid to the types of data needed, available data sources and their formats, and the needs of the propagation analysis software. These schemes were implemented in the form of several new programs that have been integrated with GRASS. Data interfacing is the major function performed by these programs. Building and terrain data may now be exchanged between GRASS and AutoCAD, a computer-aided design software package. The data analysis powers of the GIS were used for estimating diffraction path loss over terrain. The results of propagation prediction can be displayed in a graphical manner through the GIS, and hardcopy outputs are possible. The work presented here sets the framework for the integration of various software modules that can combine to form a propagation prediction tool. / Master of Science

This thesis deals with the system of education in the organization State Agricultural Intervention Fund. The thesis is divided into two parts. The first part is focused on literary research related to education in the organization. In the second part, the research was carried out and evaluated on the basis of a questionnaire survey. The current employees of the Fund were the respondents. The obtained data from the questionnaire survey was evaluated and subsequently evaluated on the basis of the knowledge from the theoretical part of the thesis.

CAPES / As cianobactérias se proliferam rapidamente em ambientes eutrofizados e podem ser capazes de sintetizar toxinas que inviabilizam a utilização dos recursos hídricos. A espécie Microcystis aeruginosa apresenta ampla distribuição, além de ser potencial produtora de hepatotoxinas denominadas microcistinas. O risco à saúde humana destas substâncias faz com que os métodos para controle destes microrganismos na água adquiram fundamental importância. De forma a verificar possíveis efeitos inibitórios de compostos fitoquímicos produzidos por macrófitas aquáticas sobre o crescimento e a produção de microcistinas da cianobactéria Microcystis aeruginosa, o presente estudo utilizou extratos hidroalcoólicos de sete espécies de macrófitas aquáticas (Eichhornia azurea, Eleocharis cf. acutangula, Ludwigia cf. peruviana, Myriophyllum cf. aquaticum, Pontederia cordata, Sagittaria montevidensis e Typha domingensis). O meio de cultura ASM-1 foi otimizado em relação ao pH, nitrogênio, fósforo e ferro através de planejamento fatorial. Para o preparo dos extratos, as sete espécies de macrófitas aquáticas foram coletadas, processadas e submetidas ao processo de extração com solução hidroetanólica 80% (v/v). Os extratos obtidos foram liofilizados e aplicados em concentrações conhecidas aos cultivos de M. aeruginosa, em meio ASM-1 otimizado. O monitoramento da concentração celular foi realizado a cada 48 h por 10 dias. As diferenças estatísticas foram avaliadas através do método estatístico ANOVA repeated. A determinação da concentração de microcistina-LR foi realizada nas culturas contendo a concentração de extrato de maior efeito inibitório. Para a verificação de efeitos bacteriostáticos e bactericidas, ao final do período testado, os cultivos foram reinoculados em tubos de ensaio contendo apenas o meio de cultura estéril. Os extratos foram avaliados quanto à presença de metabólitos secundários e à toxicidade aguda sobre Daphnia magna. Os experimentos apresentaram valores de crescimento elevados no meio que continha maiores concentrações de P e Fe. Os extratos inibiram significativamente o crescimento da cepa quando foram aplicados na concentração de 500 mg.L-1, com exceção do extrato obtido a partir de S. montevidensis em que o efeito inibitório sobre as células foi o menor observado. O extrato com maior efeito inibitório foi obtido de partes aéreas de M. cf. aquaticum pois a taxa de inibição foi de 99,1% na concentração de 500 mg.L-1. As análises de microcistina evidenciaram que para o extrato de E. cf. acutangula a redução do crescimento foi acompanhada de aumento na produção de microcistina-LR de 216 para 610 ppb. Nos testes com o extrato de S. montevidensis a concentração de toxina sofreu pouca alteração, aumentando de 216 para 222 ppb. Efeitos bactericidas foram verificados para a exposição aos extratos de E. cf. acutangula, L. cf. peruviana e M. cf. aquaticum, uma vez que após reinoculadas não foram verificados crescimentos celulares. Para os extratos de E. azurea, P. cordata e T. domingensis não foram observados efeitos tóxicos, por outro lado, a maior toxicidade ocorreu para S. montevidensis, pois 100% dos organismos apresentaram imobilidade na concentração de 50 mg.L-1. Considerando os dados de inibição e de toxicidade foi possível constatar que o extrato obtido de L. cf. peruviana apresentou maiores vantagens em sua aplicação. Os resultados obtidos indicam a possibilidade futura da aplicação de extratos para a remediação de florações e mostram, também, a necessidade de investigações fitoquímicas e toxicológicas mais detalhadas no sentido de identificar as substâncias ativas no controle de florações, de forma a potencializar a ação destas e minimizar seus efeitos tóxicos. / Cyanobacteria proliferate rapidly in eutrophic environments and may be able to synthesize toxins that block water resources use. The cyanobacterium Microcystis aeruginosa is widely distributed, being a potential producer of hepatotoxins called microcystins. The risks to human health of these substances demands methods to control these microorganisms in water. In order to investigate possible inhibitory effects of phytochemical compounds produced by aquatic macrophytes on the growth and microcystin production of Microcystis aeruginosa, the present study used aquatic macrophytes hydroalcoholic extracts of seven species (Eichhornia azurea, Eleocharis cf. Acutangula, Ludwigia cf. peruviana, yriophyllum cf. aquaticum, Pontederia cordata, Sagittaria montevidensis and Typha domingensis). The culture medium ASM-1 was optimized with respect to pH, nitrogen, phosphorus and iron through a factorial design. For extracts preparation, the seven species of aquatic macrophytes were collected, processed and submitted to extraction process solution ethanol 80% (v/v). The extracts were lyophilized and applied in known concentrations to cultures of M. aeruginosa, in optimized ASM-1 medium. Cell concentration was determined every 48 h for 10 days. Statistical differences were evaluated using ANOVA repeated. The microcystinLR concentration was determined in cultures containing greater inhibitory effect extract concentration. Evaluation of bacteriostatic and bactericidal effects at the end of tested period, the cultures were reinoculated into test tubes containing only sterile culture medium. The extracts were evaluated for the presence of secondary metabolites and acute toxicity on Daphnia magna. The experiments showed high growth rates in medium containing higher concentrations of P and Fe. Hydroalcoholic extracts inhibited the growth of Microcystis aeruginosa strain, more effective when applied at a concentration of 500 mg L-1, except for tests performed with S. montevidensis in that the mean inhibitory effect on the cells was the lowest observed. The extract with the highest inhibitory effect was obtained from aerial parts of M. cf. aquaticum in which the inhibition rate was 99.1%. The analyzes showed that microcystin for the extract of E. cf. acutangula the greatest cellular inhibition was accompanied by an increase in microcystin-LR production from 216 to 610 ppb. In tests with S. montevidensis extract the concentration of toxin was few changed, increasing from 216 to 222 ppb. Bactericidal effects were observed for exposure to extracts of E. cf. acutangula, L. cf. peruviana and M. cf. aquaticum. For extracts of E. azurea, P. cordata and T. domingensis toxic effects were not observed. The major toxicity was observed for S. montevidensis, in which 100% of organisms presented immobility in concentration of 50 mg.L-1. Considering inhibition and toxicity data was found that L cf. peruviana extract showed more advantages on its application. The results indicate the possibility of future application of extracts for blooms remediation and also show the need for detailed toxicological and phytochemical investigations in order to identify the active compounds in blooms control and minimize their toxic effects.

This thesis deals with the analysis of human resource management in the company, evaluation of personnel activities and proposing changes to improve personal work.

Notre travail de recherche porte sur l’analyse de l’action du professeur et ses interactions avec les élèves dans le domaine spécifique de l’étude du numérique en Cours Préparatoires. L’objectif de notre thèse est d’analyser l’action du professeur et ses pratiques didactiques en classes, et formatives dans une Cellule d’Animation Pédagogique. La première partie comporte une présentation du contexte socio économique et éducatif du Niger. Nous nous interrogeons ensuite sur les pratiques professorales permettant ou non aux élèves de prendre de réelles responsabilités par rapport aux savoirs, et sur la pertinence du travail de conception collective de séances. Dans la deuxième partie, nous exposons nos outils théoriques, les travaux antérieurs en lien avec nos objets de recherche, et la problématique générale de notre travail. La troisième partie est consacrée à la démarche méthodologique qui fonde notre étude sur l’analyse des manuels, des vidéos de classe et les observations in situ. La quatrième partie examine les ressources mathématiques utilisées à l’écoleprimaire au Niger, en interrogeant l’influence de ces ressources sur les pratiques habituelles des professeurs enquêtés. Les cinquième et sixième parties analysent les séances empiriques en termes de topogénèse, et de recours aux systèmes sémiotiques pour étudier le savoir en jeu dans les situations didactiques. Dans la septième partie, nous proposons un dispositif innovant de formation continue sur la conception collective de leçons dans une CAPED. En conclusion, dans une huitième partie nous présentons d’abord une synthèse de nos résultats, et nous exposons ensuite les perspectives que ce travail de recherche offre en termes de propositions en vue de l'élaboration d'ingénieries didactiques qui pourraient permettre la mise en place d’un travail coopératif entre professeurs et chercheurs / Our research focuses on the teacher's action and his interactions with students in the specific field of the study of digital in grade 2. The objective of this PhD dissertation is to analyze the teacher's action and his didactic practices in classes, and training practices in a CAPED in the Niger context. The first part of this PhD dissertation includes a presentation of the socio-economic and educational contexts in Niger. Then we examine the teaching practices in order to see if they allow students to take or not real responsibilities in relation to knowledge, and the appropriateness of collective design work sessions.In the second part, we present our theoretical tools, previous work related to our research objects, and the general problem tackled by our work. The third part is devoted to our methodological approach based on the study of textbook analyze, videos of classes and field observations. The fourth section discusses the mathematic resources used in the primary education in Niger and question the impact of these resources on the observed teachers' usual practices. The fifth and sixth sessions analyze empirical lessons in terms of topogenesis, and semiotic systems to study the knowledge involved in the didactic situations. In the seventh part, we propose an innovative in-service training based on the design of lessons in a collective CAPED. In conclusion, in an eighth part we first present a summary of our results, and then we present the perspectives that this research offers in terms of further developments of didactic engineering that could allow the implementation of a collaborative work between teachers and researchers

Consisting of both theoretical and empirical inquires, this study examines the primary functions of narrative and the relationship between narrative and mental imagery. The study proposes a new framework to interpret semiotic resources. Combining this with the linguistic functional theory of Halliday (1978), a functional method to empirically investigate semiotic representations was also developed. In the empirical inquiry, the study developed a latent construct method to empirically test the effects of narrative in a real learning situation. This study is the first to investigate the functional relationship between narrative and mental imagery, and among the first to suggest a theory and empirically investigate representations of a multimodal nature. The study is also among the first to use latent constructs to investigate the learning experience in a real educational setting. Data were collected from 190 library professionals who enrolled in three sections (two in narrative and one in plain text) of an online course administered through Vista 4.0 and who completed the course and responded to several instruments. Essay data (n = 82 x 2) were analyzed using content analysis based on the narrative analysis framework developed. Quantitative data analysis methods include univariate data analysis, factor analysis, and structural equation modeling that tests the proposed model and verifies the relationships between the latent variables. Overall, the findings support the hypotheses about the functional effects of narrative identified, and narrative is found to provide a favorable and positive learning context which is tested by the proposed model of learning experience measured by several latent constructs (X2 = 31.67, df = 47, p = .9577, RMSEA = .00, SRMR = .047, NNFI = 1.05, CFI = 1.00, and GFI = .94). The results indicate that participants who enrolled in the narrative sections of the course gained higher creative scores and showed better results in performance-based and attribution-based experiences. The model testing results indicate that even though more time spent during learning led to better outcome and performance in both groups, more time spent means more satisfaction for the individuals in the narrative group, but led to less satisfaction for the individuals in the non-narrative group.